- Synthesis Method of Cyclopropane or Cyclopentene Derivatives via Fe-catalyzed Cationic Radical Cycloaddition Reaction
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In this disclosure Fe (III) complex is used as an electron oxidizing agent to oxidize an electron - rich alkene compound to form a radical cation intermediate, and then a cyclopropane compound or 3 5-membered ring compound is synthesized by inducing a cycloaddition reaction with the diazo compound.
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Paragraph 0080-0081; 0101-0102
(2021/11/02)
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- Cycloaddition Reactions of Alkene Radical Cations using Iron(III)-Phenanthroline Complex
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Single electron oxidation of electron-rich alkenes using the iron(III)-phenanthroline complex produced electrophilic alkene radical cations, which promoted efficient radical cation [2+1] cycloaddition reactions with diazo compounds. Subsequent chain propagation afforded tri- and tetra-substituted cyclopropanes. This methodology was also expanded to [3+2] cycloaddition reactions with vinyl diazoesters, validating this sustainable, first-row transition metal iron system for the single electron redox reactions. (Figure presented.).
- Cho, Yong Hyun,Kim, Jae Hyung,An, Hyeju,Ahn, Kwang-Hyun,Kang, Eun Joo
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supporting information
p. 2183 - 2188
(2020/04/29)
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- A transition-metal-free & diazo-free styrene cyclopropanation
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An operationally simple and broadly applicable novel cyclopropanation of styrenes using gem-diiodomethyl carbonyl reagents has been developed. Visible-light triggered the photoinduced generation of iodomethyl carbonyl radicals, able to cyclopropanate a wide array of styrenes with excellent chemoselectivity and functional group tolerance. To highlight the utility of our photocyclopropanation, we demonstrated the late-stage functionalization of biomolecule derivatives.
- Herraiz, Ana G.,Suero, Marcos G.
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p. 9374 - 9379
(2019/10/22)
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- Cyclopropane-alkene metathesis by gold(i)-catalyzed decarbenation of persistent cyclopropanes
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A gold(i)-catalyzed cyclopropane-alkene metathesis has been demonstrated with two new families of cyclopropane derivatives of naphthalene and phenanthrene (benzo-fused norcaradienes). In this process, metal carbene units are transferred from a persistent
- Mato, Mauro,Martín-Torres, Inmaculada,Herlé, Bart,Echavarren, Antonio M.
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supporting information
p. 4216 - 4219
(2019/05/06)
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- Rhodium Porphyrin Catalyzed Regioselective Transfer Hydrogenolysis of C-C σ-Bonds in Cyclopropanes with iPrOH
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A new rhodium porphyrin catalyzed regioselective transfer hydrogenolysis of both activated and unactivated cyclopropanes employing iPrOH as the hydrogen source was discovered. The reaction mechanism for the C-C σ-bond activation of cyclopropanes was identified through an initial radical substitution with rhodium(II) metalloporphyrin radical to give a rhodium porphyrin alkyl, followed by hydrogenolysis with iPrOH to give the corresponding acyclic alkanes and regenerate rhodium(II) metalloporphyrin radical.
- Chen, Chen,Feng, Shiyu,Chan, Kin Shing
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supporting information
p. 2582 - 2589
(2019/07/02)
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- Radical Cation Cyclopropanations via Chromium Photooxidative Catalysis
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The chromium photocatalyzed cyclopropanation of diazo reagents with electron-rich alkenes is described. The transformation occurs under mild conditions and features specific distinctions from traditional diazo-based cyclopropanations (e.g., avoiding β-hydride elimination, chemoselectivity considerations, etc.). The reaction appears to work most effectively using chromium catalysis, and a number of decorated cyclopropanes can be accessed in generally good yields.
- Sarabia, Francisco J.,Ferreira, Eric M.
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supporting information
p. 2865 - 2868
(2017/06/07)
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- Spin-selective generation of triplet nitrenes: Olefin aziridination through visible-light photosensitization of azidoformates
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Azidoformates are interesting potential nitrene precursors, but their direct photochemical activation can result in competitive formation of aziridination and allylic amination products. Herein, we show that visible-light-activated transition-metal comple
- Scholz, Spencer O.,Farney, Elliot P.,Kim, Sangyun,Bates, Desiree M.,Yoon, Tehshik P.
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supporting information
p. 2239 - 2242
(2016/02/18)
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- Elevated catalytic activity of ruthenium(II)-porphyrin-catalyzed carbene/nitrene transfer and insertion reactions with n-heterocyclic carbene ligands
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Bis(NHC)ruthenium(II)-porphyrin complexes were designed, synthesized, and characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the trans Mi£CRR′/Mi£NR moiety, these complexes showed unprecedently high catalytic activity towards alkene cyclopropanation, carbene C-H, N-H, S-H, and O-H insertion, alkene aziridination, and nitrene C-H insertion with turnover frequencies up to 1950 min-1. The use of chiral [Ru(D4-Por)(BIMe)2] (1 g) as a catalyst led to highly enantioselective carbene/nitrene transfer and insertion reactions with up to 98 % ee. Carbene modification of the N terminus of peptides at 37 °C was possible. DFT calculations revealed that the trans axial NHC ligand facilitates the decomposition of diazo compounds by stabilizing the metal-carbene reaction intermediate.
- Chan, Ka-Ho,Guan, Xiangguo,Lo, Vanessa Kar-Yan,Che, Chi-Ming
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supporting information
p. 2982 - 2987
(2014/04/03)
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- Wittig reagents as metallocarbene precursors: In situ generated monocarbonyl iodonium ylides
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A proof of concept study was undertaken to determine the suitability of monocarbonyl iodonium ylides (MCIYs) as metallocarbene precursors. Exposing Wittig reagents to iodosylbenzene results in a pseudo-Wittig reaction that generates MCIYs in situ. These ylides are intercepted by transition-metal catalysts to generate metallocarbenes, which then undergo either dimerization or cyclopropanation reactions with a variety of alkenes. Additionally, the reaction between diazoester-derived metallocarbenes and Wittig reagents afforded cross-coupling products, illustrating a new type of olefination reaction for phosphonium ylides. Monocarbonyl iodonium ylides (MCIYs) represent a possible alternative to the use diazoketones and -esters as metallocarbene precursors. Upon treatment with iodosylbenzene, a Wittig reagent will undergo ylide transfer to generate a MCIY in situ. In the presence of transition-metal catalysts, MCIYs serve as precursors to metallocarbenes, which undergo dimerization or cyclopropanation of alkenes. tfacac = trifluoroacetylacetonate. Copyright
- Ho, Phyllis E.,Tao, Jason,Murphy, Graham K.
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supporting information
p. 6540 - 6544
(2013/11/06)
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- 1,3,5-Tris(thiocyanatomethyl)mesitylene as a Ligand. Pseudooctahedral molybdenum, manganese, and rhenium carbonyl complexes and copper and silver dimers. Copper-catalyzed carbene- and nitrene-transfer reactions
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New molybdenum(0), molybdenum(II), manganese(I), rhenium(I), silver(I), and copper(I) complexes with the 1,3,5-tris(thiocyanatomethyl)mesitylene [Ms(CH2SCN)3] ligand have been synthesized and characterized by IR, NMR, and by X-ray diffraction (except for the rhenium complex). The Ms(CH2SCN)3 ligand coordinated with the molybdenum, manganese, and rhenium carbonyl fragments as a tripodal chelate. With copper and silver, dimeric dicationic species were obtained instead, with the Ms(CH2SCN)3 ligand acting simultaneously as a bidentate chelate and bridge. The [{Cu(Ms(CH2SCN)3)} 2][BAr′4]2 (BAr′4 = tetra(3,5-bis(trifluoromethyl)phenyl)borate) product is an excellent catalyst for cyclopropanation and aziridination of alkenes and cyclopropenation of alkynes by means of carbene- and nitrene-transfer reactions.
- Martinez-Garcia, Hector,Morales, Dolores,Perez, Julio,Puerto, Marcos,Miguel, Daniel
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experimental part
p. 6974 - 6985
(2010/09/06)
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- The influence of chiral auxiliaries is enhanced within zeolites
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Zeolites significantly enhance the influence of chiral auxiliaries during photochemical reactions. The generality of this phenomenon has been tested with three independent examples. Chiral auxiliaries that lead to 1:1 mixtures of diastereomers in solution
- Jayaraman,Uppili,Natarajan,Joy,Chong,Netherton,Zenova,Scheffer,Ramamurthy
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p. 8231 - 8235
(2007/10/03)
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- Acyl guanidine sodium/proton exchange inhibitors and method
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Acyl guanidines are provided which are sodium/proton exchange (NHE) inhibitors which have the structure STR1 wherein n is 1 to 5; X is N or C--R5 wherein R5 is H, halo, alkenyl, alkynyl, alkoxy, alkyl, aryl or heteroaryl; and R1, R2, R3 and R4 are as defined herein, and where X is N, R1 is preferably aryl or heteroaryl, and are useful as antianginal and cardioprotective agents. In addition, a method is provided for preventing or treating angina pectoris, cardiac dysfunction, myocardial necrosis, and arrhythmia employing the above acyl guanidines.
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- Trans N-Methyl-N-[2-(1-pyrrolidinyl)cyclohexyl] cycloprop-2-ene-1-carboxamides: Novel lipophilic kappa opioid agonists
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The synthesis and kappa opioid agonist activities of some lipophilic analogues of the kappa opioid agonist U-50488 incorporating motifs bearing two aromatic rings in place of the 3,4-dichlorophenyl group are described. Trans 2,3-diphenyl-N-methyl-N[2-(1-pyrrolidinyl)cyclohexyl]-2-cyclopropene-1 -carboxamide, 7, is a potent kappa opioid agonist. A diphenylcyclopropene analogue of CI-977, trans 2,3-diphenyl-N-methyl-N-[7-(1-pyrrolidinyl)-1-oxaspiro[4.5]dec-8-yl]-2 -cyclopropene-1-carboxamide, 13, is a highly lipophilic chemically novel potent selective kappa opioid agonist.
- Sabin,Horwell,McKnight,Broqua
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p. 291 - 296
(2007/10/03)
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- Mechanistic criteria for cation radical reactions: Aminium salt-catalyzed cyclopropanation
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Mechanistic studies of the cyclopropanation of a series of trans-stilbenes by ethyl diazoacetate catalyzed by two different triarylaminium salts decisively confirm a cation radical mechanism and rule out a hypothetical electrophilic mechanism. The elucidation of key aspects of these cation radical mechanisms, including kinetic vs equilibrium control of ionization and chain vs catalytic mechanisms, has also been achieved for these systems. New mechanistic criteria for the positive identification of cation radical mechanisms are proposed.
- Yueh, Wang,Bauld, Nathan L.
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p. 5671 - 5676
(2007/10/02)
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- Electron Demand in the Transition State of the Cyclopropylidene to Allene Ring Opening
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The electronic structure of the transition state for the cyclopropylidene to allene conversion has been probed.The methodology involved the relative rates of ring opening vs trapping by MeOH for a series of variously substituted 2,3-diarylcyclopropylidenes.With the assumption that the rate of trapping was unaffected by substituents, a Hammett correlation was constructed.The negative value (-0.72) for ρ indicated that the carbenic center attracts electron density in the ring-opening transition state, much like the cyclopropyl cation to allyl cation transition state.Temperature-dependent studies showed that the observed preference for ring opening was driven by entropy factors.Also, using reasonable estimates for the close to diffusion-controlled trapping activation enthalpies, the derived enthalpies for ring opening were in close agreement with the best theoretical values.
- Warner, Philip,Sutherland, Robert
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p. 6294 - 6300
(2007/10/02)
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- 1,2,3-Trisubstituted Cyclopropanes as Conformationally Restricted Peptide Isosteres: Application to the Design and Synthesis of Novel Renin Inhibitors
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The 1,2,3-trisubstituted cyclopropanes 6 and 7 are the first members of a novel class of isosteric replacements for peptide linkages that are more generally represented by the dipeptide mimics 2 and 3.These unique peptide surrogates are specifically desig
- Martin, Stephen F.,Austin, Richard E.,Oalmann, Christopher J.,Baker, William R.,Condon, Stephen L.,et al.
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p. 1710 - 1721
(2007/10/02)
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